Studies on prolongation of pre-rigor period of fish - II. Remarkable differences in rigor mortis between wild and cultured specimens of the red sea bream Pagrus major.

Abstract

Wild and cultured specimens of the red sea bream Pagrus major were stored at 0°C and 10°C, and compared to each other with respect to the progress of rigor mortis. Rigor mortis began to occur earliest in the cultured specimen stored at 0°C, followed suc-cessively by the wild one at 0°C, the cultured one at 10°C, and the wild one at 10°C, demonstrating that the pre-rigor period of red sea bream can be most effectively attained in the last case. Rigor mortis of the muscle proceeded with a decreasing ATP level and an increasing lactic acid level. The lactic acid level in the muscle was higher by about 100mg/100g in the cultured than in the wild specimen, just after the instant death. On the other hand, K values of those specimens were less than 10% even after 56h of storage at 0°C or 10°C, indicating that they kept an extremely high freshness. The freshness of the muscle tended to decrease more rapidly in the cultured than in the wild specimen.